1. Field Of The Invention
The present invention pertains to a mechanically variable transmission for utilizing a constant or variable speed input and constant or variable torque input and varying the output speed and output torque. More particularly the invention pertains to a novel arrangement of sheaves and power ring in combination with a planetary to provide an infinitely variable mechanical transmission having an input sheave and an output sheave operatively connected to an output shaft and circular power ring including a means for radially positioning the power ring with respect to the input and output sheaves. The input sheave and output sheaves are axially adjustable and have an included angle of from about 0.5.degree. to 45.degree. and are connected to one another by the power ring having a generally frustro conical cross section with substantially flat side faces that is radially positionable with respect to the input and output sheaves for varying and transmitting power to the output shaft.
The balance between the power from the input sheave and output sheave provided by the radially adjustable power ring to a planetary device allows novel transmissions constructed in accordance with invention to utilize a constant or variable input speed and constant or variable input torque and provide a constant or variable output speed and a constant or variable output torque to optimize fuel efficiency, engine life and reduce pollution by allowing the engine to operate at full torque and at the minimum speed necessary to obtain the most fuel efficient mode of operation. The novel mechanically variable transmission is susceptible to computer control which can be utilized for novel transmissions constructed in accordance with the invention or that can be coupled to both the novel transmissions and engine for operating the engine at full torque with the lowest possible speed while varying the position of the power ring in relation to the sheaves to maintain a constant or desired ground speed by changing the operating ratio continuously in the novel transmission to maintain the desired speed. Transmissions constructed in accordance with the invention increase engine life and reduces fuel consumption and pollution by providing power efficiency advantages over traditional transmissions by changing speeds under load without the interruption of the power transfer required in shifting gears in response to load, speed and road conditions and the resulting raising and lowering engine RPM changes that result in the exhaust of incompletely burned fuels and gases that pollute the atmosphere when an engine is not continuously run at maximum torque at the lowest possible speed.
2. Description Of The Prior Art
In recent years extensive research has been devoted to improving engine efficiency, increasing gas mileage and reducing pollution. Very little progress has been made in improving the interface between the engine and the vehicle transmission to provide the most fuel efficient, most engine efficient and least engine polluting operation of the engine by focusing upon the engine and transmission interface to provide the most efficient transmission of engine power and torque to the operation of the vehicle. The most efficient operation of an internal combustion engine for vehicles is the operation of the engine at full torque and at the lowest possible speed necessary to maintain or attain a desired ground speed.
In prior art transmissions efficient engine operation is not possible most of the time since the gears define the operating limitations of torque and speed which require extensive shifting of gears in response to load and terrain conditions encountered in the operation of the vehicle. Vehicle speed is determined by engine RPM and gear ratio so that once the gear is selected speed is determined by engine RPM. The prior art transmissions and engine combination maximum efficiency at full load and maximum terrain since the engine is then operating at the maximum torque and the minimum speed necessary for operation at a given speed. The novel transmissions of the present invention are designed to achieve these same maximum efficiency condition at all other load and terrain condition by utilizing the novel power ring and sheaves of the invention.
Generally one third of the fuel energy is expelled as wasted combusted heat and exhaust gases, one third is friction heat, together some of the friction heat being expelled through the radiator, and the other third is useful work in the operation of the vehicle. Unfortunately the one third that is useful work is only efficiently utilized when the engine is operated a full load at which time the least amount of pollutants are discharged in the atmosphere and the greatest amount of engine efficiency is utilized.
Prior art engines and transmission combinations cannot operate at full torque at all times since current transmissions that use gears with fixed ratios require engine RPM to be constant in order to maintain a constant traveling speed. Therefore engine efficiency would be optimized by transmission system that eliminates fixed gears and allows the engine to operate at full torque but at the lowest possible speed to obtain a desired road speed and thereby reduce fuel consumption, pollution and increase the efficient operation of the engine and thereby reduce the high engine wear normally encountered in vehicles. These advantages can be obtained by the elimination of the transmissions generally utilized in vehicles and the replacement of those transmissions with a transmission device which allows the engine to be operated at maximum torque irrespective of the road conditions but at lowest possible speed and instead of varying engine speed vary the transmission ratio in order to obtain and maintain a particular desired speed.
The prior art has recognized the advantages of utilizing an infinitely variable bidirectional power transmission such as illustrated in U.S. Pat. Nos. 4,406,178; 4,644,820; 4,546,673; 2,889,716; 4,553,450 and U.K. 2,115,091 employ variable speed pulleys that are connected by either belts or chains in combination with various forms of planetary gears to provide a variable drive. The problems with such prior art devices is the load forces coupled with friction cause the belts to wear and break and the chains to lag and lead around the pulleys or gears. These forces coupled with the elastic nature of chains and belts do not provide a positive drive. Such prior art does not teach or suggest the utilization of a combination of a solid power ring having load bearing side faces with adjustable sheaves to provide an efficient transmission and division of power.
In addition such prior art does not utilize a computer for interfacing the transmission with the power source to provide for the maximum torque output for the internal combustion engine while maintaining the minimum speed while varying the transmission of power between the input and output sheaves to obtain maximum engine and fuel efficiency. The inapplicability of computer control of such prior art devices may also be the result of the elasticity of belts and chains under varying load conditions which make the application of computer control to such prior art inefficient and difficult for failing to provide a reliable and consistent power transfer.
Other prior art such as U.S. Pat. Nos. 4,718,012 and 4,546,673 pertain to variable speed transmission which include various computer controlled and assisted arrangements for optimizing power output and coordinating the variable transmission with variable engine speed. These prior art systems utilize computer control of belts (4,546,673) and hydraulic systems (4,718,012) which are difficult and complicated to control as a consequence of the elasticity of the belts and compressibility of the fluids. These prior art systems do not teach or suggest a system of positive control employing a substantially inelastic metal power ring in combination with adjustable sheaves for providing substantially instantaneous and positive power that can be effectively controlled by a computer. The prior art systems are inefficient and expensive as a consequence of their design of employing belts, chains and hydraulic flow lines in combination with a computer present serious limitations as a result of the inherent fluid compressibility and flow characteristics of fluids. Such systems result in the inefficient use of computers and instantaneous computer generated change as a result of the lag for the hydraulics and belts and chains.
The only prior art known to employ an apparently solid power ring is German Patent No. 185,184 which schematically illustrates a variable speed transmission having an input sheave and an output sheave connected by circular metal power ring with a round cross section that is apparently is utilized in a soap press for making allowances for the varying consistencies of processed soap. This device does not pertain to automobiles or vehicle transmissions and is a speed as opposed to a power transmission device as it does not employ a power ring of a configuration necessary to transfer power between adjustable sheaves. German patent No. 185,184 does not teach or suggest the Applicant's transmission nor does it teach or suggest the utilization of a computer for varying the torque and speed of the transmission while maintaining full torque and optimum speed for the internal combustion engine or the interface between an automobile engine and the transmission.
The inefficiencies of the prior art system are eliminated in accordance with the invention by providing a positive geared relationship between the input and output shaft and the input and output sheaves with a power ring to provide a responsive transmission suitable for providing a mechanically infinitely variable speed that can be controlled with a computer. The novel combination of adjustable sheaves and power ring provides a mechanically infinitely variable transmission that is adaptable to computer control for the output of an internal combustion engine to maximize fuel efficiency, minimize pollution and wear on the internal combustion engine. The geared relationship between the sheaves and the output shaft and the engine allows the engine to be operated at full torque while operating at a speed which provides the most fuel efficient mode of operation in relation to the road conditions and load conditions of the vehicle.
The positive geared relationship between the elements of the novel infinitely variable transmission allows the transmission to vary output speed smoothly from maximum rotational speed in one direction to maximum rotational speed in the opposite direction while passing through or maintaining zero output speed, or any other speed, in a forward or reverse direction while the output speed remains constant or also varies. The change in output speed over the entire range can be made continuously under full load as no declutching is necessary to shift the gears and, in addition, eliminates belts, fluids and other elastic devices that prevent a positive control of the transmission. The present metal power ring in combination with the adjustable sheaves and a planetary device provides an inexpensive, efficient and direct gearing system which allows the entire device to be controlled by a computer to provide fuel efficiency, increased engine life and decreased pollution.